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basic wiring question

12-29-2007, 09:41 AM

I had my workshop wired by an electrician a while back and had him rough wire an outlet for a welder in the eventuality I would get one. The time has come and the new MM 180 will be here on Monday. The electrician had done everything but install the actual plug and had covered the outlet box with a solid cover and had marred the end of the wires. I went out this AM and bought a welding 250v plug and decided to install it but the plug has room for 3 wires (grd + 2 wires) and the installed wire contains 4 (grnd+3 wires). Which 3 do I use on the plug ? The elctrical box has the red and black wire fastened on the breaker, the groung where all other grounds are and the white is where all other whites are. Is it possible that the electrician only needed a 3 strand wired and only had a 4 strand wire on hand ? Asside from taking a part my dryer outlet to see how this is done can any of you help me out ?

Your electrician wired your welder outlet to meet any requirements you might need (assuming he used large enough wire). The black and red wires from the breaker and the green ground are all you need. Just leave the white wire capped and rolled up inside the box. The white wire is the neutral and not used on your new outlet. Good luck and congrats on your new welder.

Comment

The red and black run from the 220v breaker correct?....the green and white are running from where?....it sounds like the green is grounded on the breaker box........
Mike
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Comment

Comment

Yes, the red and black run from the breaker but the green grnd that both of you speak about isn't green, it's bare copper. It is fastened where all other bare copper wires are fastened inside the electrical box .

Comment

Yes, the red and black run from the breaker but the green grnd that both of you speak about isn't green, it's bare copper. It is fastened where all other bare copper wires are fastened inside the electrical box .

The bare copper wire is the ground. They are coated with green insulation in some cables and bare in others.

Can you see any writing or stamped numbers on the outer insulation (look in the breaker box)? It is important that the wire size match the amp rating for the breaker. I'm sure the electrician used the correct wire size as this is not an uncommon job, but it's always good to know. You'll be looking for numbers like 10/3, 8/3. Let us know what you find.

Comment

the wire is a 10-3 wire 300 v. While we're on the subject, the breaker in the workshop is a double 30 amp. The breaker at the house is also a 30 amp but someone suggested upgradding this to a double 50 or 60 amp once the welder is installed. The wire between both electrical boxes is an outdoor rated 6-3.

Comment

the wire is a 10-3 wire 300 v. While we're on the subject, the breaker in the workshop is a double 30 amp. The breaker at the house is also a 30 amp but someone suggested upgradding this to a double 50 or 60 amp once the welder is installed. The wire between both electrical boxes is an outdoor rated 6-3.

Does this sound OK to you ?

The breaker in the house panel feeding the sub-panel via #6-3 wire should be a 60 amp.

I have about 20 ft of exterior grade 10/3 wire. would this be suitable for an extension cord for the mm180 if i conect the right male and female connections to it ?

That wire is not "REALLY" suitable for extension cord. Flexing from movement causes cracks leading to voltage drop which creates heat. Enough voltage drop creating enough heat causes fires. ANY voltage drop will adversely affect welder operation and enough drop (long before the fire) will kill the circuits in the welder. Not good. That job calls for SJ, SO, SJTOW, or similar cable because there are more, smaller conductors which lend themselves to flexing. When I am making a short extension cord, I troll through the electrical departments at my local Home Depot and Lowe's looking for miscuts, extras and short pieces left from the roll. They'll almost always sell it for significantly less than regular price.

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thanks Triggerman, I'll do the same when out at the hardware store. Should I be looking for 8/3 or will 10/3 do. I see that the cord on the actual mm180 is a 12/3.

Sice my last post I picked up my new mm180 and tried it out. My first time welding. I used fluxed core wire as I am not set up with gas yet. It went pretty well, but not well enough to send picks yet There was quite a bit of puddles and spatter. Once I brushed the spatter off it didn't look too bad. I see what you all nean now by practice, preactice , practice. It's kind of unatrual handling the mask, trigger and positionning the gun all at once, not to mention using the proper technique.

As mentioned in past posts, I have a wooden floor in my shop. This didn't do too much dammage, but I can see that welding on it for years will dammage it quite a bit and could be dangerous for fires. I'm still looking for a cheap way to cover this floor.

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The breaker in the house panel feeding the sub-panel via #6-3 wire should be a 60 amp.

That wire is not "REALLY" suitable for extension cord. Flexing from movement causes cracks leading to voltage drop which creates heat. Enough voltage drop creating enough heat causes fires. ANY voltage drop will adversely affect welder operation and enough drop (long before the fire) will kill the circuits in the welder. Not good. That job calls for SJ, SO, SJTOW, or similar cable because there are more, smaller conductors which lend themselves to flexing. When I am making a short extension cord, I troll through the electrical departments at my local Home Depot and Lowe's looking for miscuts, extras and short pieces left from the roll. They'll almost always sell it for significantly less than regular price.

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I'm trying to upload my picks from the "manage attchements" available on the forum. It's telling me my files are too big. Should be no bigger than 488 and mine are all in the 500 or 600's. Can anyone help me withy this. ?